
Mariage-kei medaka are celebrated for their striking tri-color pattern of vermilion, white, and black — a palette as festive as the wedding their name evokes. Hardy and easy to breed, they appeal to beginners and experienced hobbyists alike.
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Mariage-kei is a selectively bred medaka variety developed by Japanese breeders over many years of refining tri-color bloodlines. The name "Mariage" (French for "marriage") evokes the festive harmony of vermilion, white, and black blending together on a single fish. Multiple lineages exist, including long-finned variants, and because each individual carries a unique pattern, the variety holds strong appeal for collectors. Temperament is gentle, making Mariage-kei suitable for both indoor aquariums and outdoor biotope setups. Keeping them in dark-colored containers enhances color contrast noticeably. Careful selection of parent fish with vivid, balanced markings allows the quality of patterning to improve across generations, rewarding breeders with increasingly striking results. This variety offers both the joy of breeding and high ornamental value.
1Color Expression Varies Widely
Each Mariage-kei fish carries a unique distribution of red, white, and black, so no two look identical. Check live photos or breeder images carefully before purchasing, and keep in mind that the pattern can shift as the fish matures.
2Ideal Temperature: 15–28°C
Like most medaka, Mariage-kei thrive between 15°C and 28°C. Guard against summer overheating from direct sunlight and sudden winter temperature drops. Outdoors, adjust placement and shading with the seasons.
3Slightly Alkaline Water Is Best
A slightly alkaline pH of 7.0–7.5 suits Mariage-kei best. Adding a small amount of oyster shell helps stabilize pH. Perform partial water changes of about one-third weekly, and avoid sudden chemistry swings.
4Dark Containers Enhance Color
Using a black or deep-navy container makes the tri-color contrast pop, especially the red and white tones. White containers can wash out the colors, so choose dark vessels if you want the best visual impact.
5Easy to Breed, Selection Matters
Mariage-kei breed readily and lay eggs on aquatic plants or spawning mops. However, fry vary in color quality, so selecting parent fish with vivid, well-balanced patterns is key to producing attractive offspring over generations.
6Cost Varies with Pattern Quality
Prices range from a few hundred yen for entry-grade fish to several thousand yen or more for prized specimens with exceptional patterning. Budget around ¥10,000–¥20,000 upfront to cover a container, filtration, and spawning materials.